Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 010014 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 713 PM EST SAT JAN 31 2015 .SYNOPSIS... WARM ADVECTION PRECIPITATION EARLY SUNDAY. LOW PRESSURE SYSTEM PASSES NORTH OF THE AREA LATE SUNDAY NIGHT. MUCH COLDER AIR BLOWS IN ON MONDAY. HIGH PRESSURE BUILDS IN MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /THROUGH SUNDAY/... 700 PM UPDATE... FINE-TUNED POPS BASED ON SREF AND LOCALLY RUN WRFARW AND WRFNMM. THIS TIGHTENS UP THE GRADIENT A BIT AND REFLECTS A BIT OF A DAGGER SE INTO WV EARLY MON MORNING...AHEAD OF THE WARM FRONT ASSOCIATED WITH THE UPCOMING SYSTEM. STILL LOOKING AT A MINIMAL FZRA POTENTIAL OVER A SMALL PORTION OF THE MIDDLE OHIO VALLEY ON THE ORDER OF A FEW HUNDREDTHS OF AN INCH ICE ACCRETION. PREV DISCN... MODELS CONTINUE TO STAY WITH THE CURRENT WARM WEDGE SOLUTION OVER MUCH OF CWA. GENERALLY USED A BLEND OF SREF AND GFS FOR POPS. ONLY REAL SIGNIFICANT CHANGE WAS TO INCLUDE A DRY SLOT ACROSS MUCH OF THE CWA FOR SUNDAY. HAVE WARM ADVECTION PRECIP MOVING IN PRE-DAWN SUNDAY MORNING. TEMPS...AND THUS PRECIP TYPE FOR THIS TIME ARE A LITTLE TRICKY...AND HINGE ON HOW QUICKLY THE CLOUDS THICKEN UP AND STOP A RADIATIVE COOLING TONIGHT. ON TOP OF THAT...DRY AIR MAY WET BULB SOME. ENDED UP WITH A FAIRLY BRIEF PERIOD OF WINTRY MIX ACROSS SOUTHWESTERN AND WESTERN ZONES...WITH SNOW FARTHER NORTH. WILL MENTION POTENTIAL OF VERY LIGHT ICING IN HWO. THIS IS NOT REALLY A SITUATION LIKE LAST FREEZING RAIN EVENT EARLIER THIS WEEK WHERE TEMPS SURGED INTO THE UPPER 30S WITH ROADS STILL BELOW FREEZING. ROAD SURFACES TODAY SHOULD BE RELATIVELY WARM DUE TO SUNSHINE...AND SHOULD NOT GET AS COLD OVERNIGHT AS CLOUDS MOVE IN. STILL...CAN ENVISION SOME PATCHY SLICK SPOTS EARLY SUNDAY MORNING. FARTHER NORTH...IT SHOULD BE MAINLY SNOW POSSIBLY MIXED WITH SOME SLEET THROUGH MID MORNING. 850MB TEMPS CONTINUE TO WARM SUNDAY...AND HAVE RAIN ACROSS ENTIRE FORECAST AREA BY MID AFTERNOON...EXCEPT FOR JUST A COUPLE OF THE HIGHEST SPOTS IN THE NORTHERN MOUNTAINS. WITH THE DRY SLOT...AND SOME DOWNSLOPE COMPONENT TO THE WIND...REDUCED CLOUD COVER IN EASTERN LOWLANDS...AND BOOSTED AFTERNOON HIGHS ROUGHLY 5 DEGREES OVER PREVIOUS FORECAST FOR THIS SAME AREA. IN COORDINATION WITH SHORT TERM FORECASTER...GOING WITH A WINTER WEATHER ADVISORY FOR PERRY AND MORGAN COUNTIES IN OHIO WITH 1-3 INCHES OF SNOW SUNDAY MORNING AND THEN ALSO COVERING THE SNOW THAT FALLS SUNDAY NIGHT INTO MONDAY. WILL ALSO CONTINUE THE BUFFER ZONE AROUND THE ADVISORY CURRENTLY IN THE HWO...ALLOWING FOR SOME SHIFT IN LOW TRACK AND INHERENT THERMAL PROFILE CHANGES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... LOW PRESSURE STARTING TO MOVE THROUGH OHIO VALLEY REGION AT THE START OF THE SHORT TERM PERIOD. BASED ON THE NORTHERN PATH OF THE LOW...WILL SEE A WARM SURGE OF AIR ACROSS THE AREA...WITH THE BULK OF PRECIPITATION STARTING OUT AS RAIN ACROSS THE AREA. THE LOW WILL GRADUALLY MOVE OFF TO THE NORTH AND EAST OF THE AREA LATE SUNDAY NIGHT/EARLY MONDAY...WITH MUCH COLDER AIR RUSHING INTO THE AREA BEHIND THE LOW...WITH A GRADUAL CHANGE OVER FROM RAIN...TO SNOW. SOUTHEAST OHIO WILL SEE A CHANGE OVER FIRST...WITH CHANGE OVER FROM RAIN TO SNOW GENERALLY AFTER 2 AM. MUCH OF THE WEST VIRGINIA LOWLANDS WONT START TO SEE A CHANGE OVER TO SNOW UNTIL AFTER DAWN ON MONDAY. AS THE COLDER AIR IS FINALLY ABLE TO WORK ITS WAY IN ENOUGH FOR A CHANGE OVER TO SNOW...THE BULK OF MOISTURE WILL GRADUALLY EXIT WITH THE EXIT OF THE LOW TO THE EAST. AS A RESULT...FIGURING ONLY LIGHT ACCUMULATIONS FOR MUCH OF THE AREA...WITH GENERALLY 2 TO 4 INCHES POSSIBLE ACROSS PERRY COUNTY....WITH 1 TO 3 IN MORGAN COUNTY...AND AROUND AN INCH FOR THE REMAINDER OF SOUTHEAST OHIO. EXPECT MUCH OF THE WEST VIRGINIA LOWLANDS TO RECEIVE AROUND AN INCH OR LESS...EXCEPT NORTHERN WEST VIRGINIA LOWLAND COUNTIES SUCH AS CLARKSBURG AREA...WHERE A GOOD INCH OR TWO IS POSSIBLE. MOUNTAINOUS COUNTIES COULD EASILY GET 2 TO 4 INCHES...WITH ADDITIONAL ACCUMULATIONS POSSIBLE ON NW FACING SLOPES. THE SNOW WILL TRANSITION FROM A HEAVY WET SNOW...TO A LIGHTER FLUFFIER SNOW AS THE DAY PROGRESSES ON MONDAY AS 850MB -16C AIR RUSHES INTO THE REGION. THIS SHOULD ALLOW FOR ACCUMULATIONS IN THE HIGHER TERRAIN COUNTIES IN LINGERING UPSLOPE FLOW. WE WILL ISSUE A WINTER WEATHER ADVISORY FOR PERRY AND MORGAN COUNTIES THROUGH MONDAY MORNING. WILL KEEP AN EYE ON THE POTENTIAL FOR MOUNTAINOUS COUNTIES. HIGH PRESSURE WILL BUILD IN FOR TUESDAY...WITH DRY CONDITIONS...AND MODERATING TEMPERATURES. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... BROAD EASTERN MID/UPPER LEVEL TROF WITH FAST FLOW...AND FEW OPPORTUNITIES TO ACCESS THE GULF OF MEXICO MOISTURE. WEAK WARM AIR ADVECTION ONGOING TUESDAY NIGHT...WILL TRY TO BRING SOME 20/30 POPS A BIT FASTER SOUTH BY DAWN WEDNESDAY INTO OUR NORTHERN COUNTIES. 12Z GFS A BIT MORE AGGRESSIVE WITH THE MOISTURE MOVING UP THE OHIO VALLEY WEDNESDAY ALONG THAT FRONTAL BOUNDARY. ECMWF CERTAINLY NOT AS MOIST. FOR NOW...WILL KEEP POPS IN CHANCE CATEGORY WITH FRONT WEDNESDAY INTO WEDNESDAY NIGHT. HAVE COLDER AIR BLOWING SOUTH AGAIN OVERNIGHT WEDNESDAY NIGHT INTO THURSDAY. WENT COLDER THAN OUR PREVIOUS FORECAST. DRYING AGAIN THURSDAY NIGHT THRU FRIDAY NIGHT. IN THE FAST FLOW...NEXT SYSTEM COULD ARRIVE BY LATE DAY 7. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR START...BUT HIGH PRESSURE DEPARTS IN FAVOR OF A LOW PRESSURE SYSTEM APPROACHING FROM THE W THAT WILL REACH THE LOWER OHIO VALLEY BY THE END OF THE TAF PERIOD...00Z MON. ITS WARM FRONT WILL BRING A ROUND OF MVFR TO IFR CONDITIONS IN MIXED WINTRY PRECIPITATION MAINLY ACROSS THE MIDDLE OHIO VALLEY AND NRN WV...BEFORE LIFTING N OF THE AREA BY 00Z MON. WITH THE CHANCE FOR FREEZING RAIN MINIMAL BASED ON THERMAL PROFILES...HAVE GENERALLY A SNOW TO SLEET TO RAIN TRANSITION SUN MORNING. FOR PKB...THIS SNOW / TRANSITION IS CODED FOR 09-16Z SUN WITH MVFR VSBY AND CIGS. VSBY BECOMES VFR AS THE RAIN DIMINISHES SUN AFTERNOON...AND CIGS MAY ALSO CLIMB ABOVE 3 KFT FOR A MAINLY VFR AFTERNOON. FOR CKB...THE TIMING IF 12-16Z BUT WITH SNOW POSSIBLY BRINGING A BRIEF PERIOD OF IFR. FOR EKN...THE SNOW / TRANSITION TIME IS 14-17Z WITH MAINLY MVFR CONDITIONS. CKB AND EKN WILL ALSO SEE IMPROVEMENT SUN AFTERNOON AS THE RAIN DIMINISHES. SOUTHERN SITES HTS...CRW AND BKW WILL HAVE VFR THROUGH THE PERIOD WITH ALTOCU...ALTHOUGH AN MVFR STRATOCU DECK COULD BRIEFLY SNEAK AS FAR SE AS CRW BEFORE DAWN SUN MORNING. THE CHANCE FOR RAIN STARTS TO INCREASE QUICKLY FROM W TO E LATE SUN...AS THE COLD FRONT ASSOCIATED WITH THIS SYSTEM APPROACHES FROM THE W. LIGHT AND VARIABLE SFC FLOW OVERNIGHT WILL BECOME S ON SUN AND FRESHEN TO NEAR 10 KTS...AND BECOME A BIT GUSTY ON THE MOUNTAIN RIDGES...SUN AFTERNOON. UP N FROM PKB TO CKB...SFC FLOW WILL REMAIN LIGHT AND EVEN BACK TO SE AGAIN LATE IN THE DAY. MODERATE NW FLOW ALOFT OVERNIGHT BECOMES LIGHT TO MODERATE W SUN MORNING...AND THEN LIGHT TO MODERATE SW SUN AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY... FORECAST CONFIDENCE: HIGH EARLY ON...DESCENDING TO MEDIUM. ALTERNATE SCENARIO: TIMING OF DROPS IN FLIGHT CONDITIONS AND DEGREE AND DURATION OF WORST CONDITIONS MAY VARY. TIMING OF PRECIP TYPE TRANSITIONS MAY ALSO VARY AND...WHILE NOT EXPLICITLY CODED UP...FZRA IS A POSSIBILITY PKB...CKB...EKN...AND EVEN A SLIGHT CHANCE FREEZING RAIN EARLY SUN MORNING HTS AND CRW. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SUN UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H M PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H H AFTER 00Z MONDAY... IFR CONDITIONS POSSIBLE IN SNOW LATE OVERNIGHT SUNDAY NIGHT OVER THE MIDDLE OHIO VALLEY...AND THE HIGHER WV MOUNTAINOUS TERRAIN....LINGERING IN AND NEAR THE WV MOUNTAINS INTO MONDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...WINTER WEATHER ADVISORY FROM 1 AM SUNDAY TO 10 AM EST MONDAY FOR OHZ066-067. KY...NONE. VA...NONE. && $$ SYNOPSIS...MZ/SL NEAR TERM...TRM/MZ SHORT TERM...SL LONG TERM...KTB AVIATION...TRM

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